1. Field of the Invention
The present invention relates to a lip type seal corresponding to one kind of a sealing apparatus, and more particularly to an installation structure thereof. The lip type seal in accordance with the present invention is used, for example, as a water pump seal for a vehicle such as a motor vehicle, or is used as another general purpose water pump seal.
2. Description of the Conventional Art
Conventionally, as shown in FIG. 3, there has been known a lip type seal 74 which is installed to an inner periphery of a shaft hole 72 of a housing 71, and slidably in close contact with a peripheral surface of a shaft 73 inserted to the shaft hole 72, however, an installation structure to an inner periphery of the shaft hole 72 is made such that an outer peripheral surface of the seal 74 is directly fitted to an inner peripheral surface of the shaft hole 72. Accordingly, in the case of using it at such an installation position where a diameter of a shaft is the same but a diameter of a shaft hole is different, there is a problem that it is necessary to independently manufacture a seal 74 having the different specification in which an outer diameter is differentiated (refer to Japanese Unexamined Patent Publication No. 8-75008).
Further, as another conventional art relating to the present invention, Japanese Unexamined Patent Publication No. 2003-42304 discloses a sealing apparatus having a retainer made of a sheet metal and attached to a housing such as a cylinder block of an engine or the like, and an oil seal retained by the sheet metal retainer and slidably in close contact with a rotating member such as a crank shaft or the like, in which the sheet metal retainer and the oil seal are independently formed from each other, and the oil seal is fitted to an inner periphery of the sheet metal retainer. However, in this conventional art, the sheet metal retainer is provided for installing the oil seal to an outer end surface of a housing, and is formed as a different structure from the present invention in which the cartridge is provided for installing the lip type seal to the inner periphery of the shaft hole (refer to Japanese Unexamined Patent Publication No. 2003-42304).